JP2005296729A - Dust scattering prevention method and dust scattering inhibitor aqueous solution - Google Patents

Abstract

A dust scattering prevention method and a dust scattering inhibitor aqueous solution, in which a solid dust discharged from a garbage incinerator is kneaded with a dust scattering inhibitor aqueous solution containing polyvinyl alcohol.
[Effects] According to the present invention, it is possible to effectively prevent dust from being scattered from solid waste discharged from a garbage incinerator. In addition, it is possible to improve the working environment in the work of loading and transporting solid waste from the treated product pit, the treated product bunker or the like, or the landfilling operation at the final disposal site.
[Selection figure] None

Description

  The present invention relates to a method for preventing dust from being scattered from solid waste such as incineration ash, incineration fly ash, and burning husk discharged from a garbage incinerator, and a dust scattering inhibitor aqueous solution used therefor.

  The exhaust gas discharged from the garbage incinerator contains soot and acid substances (eg, hydrogen chloride, sulfur oxides) called incineration fly ash. The acidic exhaust gas and incineration fly ash are separated and are acidic. The exhaust gas is treated by an alkali aqueous solution or a method of neutralizing by contacting with an alkaline substance.

  On the other hand, incinerated fly ash separated from acidic exhaust gas contains harmful substances such as heavy metals, is in a fine powder form and has a low bulk specific gravity, and thus tends to generate dust and scatter. For this reason, it is environmentally problematic to discard the incinerated fly ash as it is, and the incinerated fly ash is sent to a final disposal site after being subjected to a predetermined treatment. Incineration fly ash treatment includes melting and solidification treatment (ie, treatment using incineration fly ash as slag in a melting furnace), cement solidification treatment (ie treatment for solidifying heavy metals and heavy metals with cement), chemical treatment (ie. , A process of mixing a heavy metal fixing agent such as a chelating agent solution and soot), a stabilization process with an acid or other solvent (that is, a process of elution of heavy metal by bringing dust into contact with a solvent such as an acid), etc. .

  It is preferable that the processing product obtained by such processing is difficult to generate dust in terms of work such as transportation to the final disposal site, but it can be obtained by a chemical processing method or a stabilization processing method using an acid or other solvent. The treated product has a problem that the incineration fly ash is not sufficiently fixed and is still likely to generate dust. In addition, in the processing product generated by the cement solidification processing method, when the processing product collapses during the transportation or the like, dust may be generated from the collapsed product.

  In addition, since dust generation of incineration fly ash becomes a problem in the work environment even in the work of incineration fly ash treatment, in general, in the work of incineration fly ash treatment, water is sprayed on the incineration fly ash in advance or In addition, incineration fly ash is fixed using water, such as granulation or compression molding to solidify the incineration fly ash. However, as described in Aoki et al.'S research report (Urban Cleaning, Vol. 53, No. 235, May 2000, pp. 222-225: Non-Patent Document 1), In the case of processing by the melt solidification processing method, there is a problem that the heat efficiency of the melting furnace is lowered because the amount of heat for evaporating water is required.

  Furthermore, solid waste discharged from a garbage incinerator includes incineration ash and residues in addition to the above-mentioned incineration fly ash, and dust generation is a problem even during these processing operations.

  The prior art document information relating to the present invention includes the following.

JP 2000-159316 A Japanese Patent Laid-Open No. 2003-1219 JP 2003-24916 A “Urban Cleaning”, Vol. 53, No. 235, May 2000, p. 222-225 “Urban Cleaning”, Vol. 56, No. 255, September 2003, p. 480-486

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for effectively preventing dust from scattering from solid waste discharged from a waste incinerator and an aqueous solution for dust scattering prevention.

  As a result of intensive investigations to achieve the above object, the present inventors, as a result of solid waste discharged from a garbage incinerator, an aqueous dust scattering inhibitor solution containing polyvinyl alcohol, preferably together with polyvinyl alcohol, By kneading a water retention agent, preferably a dust scattering inhibitor aqueous solution containing a natural water retention agent, the kneaded polyvinyl alcohol adheres and aggregates fine powders that can become dust in solid waste such as incineration fly ash. Thus, the inventors have found that the generation of dust can be effectively prevented with a small amount of addition, and have reached the present invention.

Accordingly, the present invention provides the following dust scattering prevention method and dust scattering inhibitor aqueous solution.
[Claim 1] A dust scattering prevention method comprising kneading a solid dust discharged from a refuse incinerator with a dust scattering inhibitor aqueous solution containing polyvinyl alcohol.
[Claim 2] The method for preventing dust scattering according to claim 1, wherein the polyvinyl alcohol content in the aqueous solution is 30% by mass or less.
[Claim 3] The dust scattering prevention method according to claim 1 or 2, wherein a polyvinyl alcohol component is kneaded at 3 parts by mass or less with respect to 100 parts by mass of the solid waste.
[Claim 4] The dust scattering prevention method according to any one of claims 1 to 3, wherein the dust scattering inhibitor aqueous solution further contains a water retention agent.
[Claim 5] The dust scattering prevention method according to claim 4, wherein the content of the water retention agent in the aqueous solution is 2 mass% or less.
[Claim 6] The dust scattering prevention method according to any one of claims 1 to 5, wherein the solid waste is incineration fly ash.
[Claim 7] An aqueous dust scattering inhibitor aqueous solution for solid waste discharged from a garbage incinerator, comprising polyvinyl alcohol.
[Claim 8] The dust scattering inhibitor aqueous solution according to claim 7, further comprising a water retention agent.
[Claim 9] The dust scattering inhibitor aqueous solution according to claim 7 or 8, wherein the solid waste is incinerated fly ash.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to prevent effectively the scattering of the dust from the solid waste discharged | emitted from the garbage incinerator, and the solid waste is carried out and carried in the garbage incinerator, for example, the processed material. It is possible to improve the work environment in the work of loading and transporting solid waste from a pit, a treated product bunker or the like, or a landfill operation at a final disposal site.

Hereinafter, the present invention will be described in more detail.
The dust scattering prevention method of this invention knead | mixes the dust scattering inhibitor aqueous solution containing polyvinyl alcohol (PVA) with respect to the solid waste discharged | emitted from the garbage incinerator. In particular, as a method to which this method can be suitably applied, a treatment process of incineration fly ash discharged in a garbage incineration facility can be mentioned.

  FIG. 1 is a schematic diagram showing an example of a process for treating incineration fly ash discharged from a waste incinerator and separated from exhaust gas in a waste incineration facility. In this case, the incineration fly ash a separated from the exhaust gas is temporarily stored in the fly ash silo 1 and supplied to the kneading and molding machine 3 by the quantitative supply device 2. The kneading and forming machine 3 is generally based on a method such as mixing a heavy metal fixing agent such as a chelating agent mixed with incineration fly ash to prevent elution of heavy metals contained in incineration fly ash, or solidifying with cement such as hydraulic cement. Although provided for the purpose of solidifying incineration fly ash, the method of the present invention can be carried out, for example, by adding an aqueous dust scattering inhibitor solution containing polyvinyl alcohol to this kneading and molding machine. is there.

  In the present invention, the dust scatter inhibitor aqueous solution contains polyvinyl alcohol, but polyvinyl alcohol is biodegradable, and the treatment product obtained by treatment with the dust scatter inhibitor aqueous solution is landfilled at the final disposal site. In view of the above points, it is superior in terms of environmental load. As the polyvinyl alcohol, either partially saponified PVA or completely saponified PVA can be used, but those having a saponification degree of 82 to 99%, particularly 82 to 90% are preferable in terms of solubility and dispersibility during kneading. . As such, commercially available products such as JL-05E manufactured by Nippon Vinegar Poval Co., Ltd. can be used.

  Further, in the present invention, since the dust scattering inhibitor is an aqueous solution, the addition to the kneading and molding machine can be carried out by a method of handling the liquid, which is preferable in that a pump or the like can be used for the addition. It is. Moreover, it is preferable also from the point that a water | moisture content is simultaneously added to incineration fly ash. Further, the aqueous solution is advantageous in terms of operation management because there is no fear of clogging with the dust scattering preventing agent in the apparatus piping. In addition, it is preferable that the content rate of the polyvinyl alcohol in a dust scattering inhibitor aqueous solution is 30 mass% or less, especially 18 mass% or less. When the content rate of polyvinyl alcohol in the aqueous solution for preventing dust scattering exceeds 30% by mass, the polyvinyl alcohol may remain undissolved or may be precipitated due to a temperature change in the process. On the other hand, the lower limit of the content of polyvinyl alcohol in the aqueous solution for preventing dust scattering is not particularly limited, but is usually 4% by mass or more, preferably 10% by mass or more.

  Furthermore, as the dust scattering preventing water solution of the present invention, those containing a water retaining agent, preferably a natural water retaining agent, together with polyvinyl alcohol are also suitable. When the water retention agent is kneaded into the solid waste, it mainly functions as a water retention / thickening agent, and even when the solid waste is exposed to a high temperature and dry environment during the kneading into the solid waste, Polyvinyl alcohol can be effectively dispersed in solid waste, and moisture can be well retained in the obtained kneaded molded product, and the caking property of polyvinyl alcohol to solid waste is high. This is advantageous in that it can be maintained. Examples of water retention agents include alginic acid compounds, and examples of alginic acid compounds include alginates such as alginic acid, sodium alginate, and potassium alginate. In addition, it is preferable that the content rate of the water retention agent in the dust scattering inhibitor aqueous solution is 2% by mass or less, particularly 0.5% by mass or less. If the content of the water retention agent in the dust scatter inhibitor aqueous solution exceeds 2% by mass, the viscosity of the dust scatter inhibitor aqueous solution may become too high, making it difficult to handle as a liquid. On the other hand, the lower limit of the content of the water retention agent in the aqueous dust dispersion preventing agent solution is not particularly limited, but is usually 0.1% by mass or more, preferably 0.2% by mass or more.

  The kneading operation can be applied as it is the kneading operation for the purpose of mixing the heavy metal fixing agent mixed in the incineration fly ash and solidifying the incineration fly ash in order to prevent the elution of the heavy metals contained in the incineration fly ash described above, Although not particularly limited, for example, by a kneader or a kneading machine equipped with a stirring blade rotating at a peripheral speed of 3 to 20 m / s in a temperature range of room temperature to about 120 ° C., particularly 20 to 100 ° C. It can be kneaded. As the kneading machine and the kneading and forming machine, a biaxial forced kneading type, a biaxial paddle type, a vibration type, a pan type and the like can be used.

  As a method of supplying the dust scattering inhibitor aqueous solution to a kneader or the like, as shown in FIG. 1, the dust scattering inhibitor aqueous solution b is pumped from the dust scattering inhibitor aqueous solution tank 4 to the kneading molding machine 3 (not shown). ) Is used. In this case, the dust scattering inhibitor aqueous solution may be supplied directly to a kneader or the like alone, mixed with another agent to be supplied to the kneader, that is, a heavy metal fixing agent, cement, or the like, or a supply line thereof. It is also possible to supply them after joining them. In addition, it is preferable that the kneading | mixing amount of a polyvinyl alcohol component is 3 mass parts or less with respect to 100 mass parts of solid waste, especially 1.5 mass parts or less. On the other hand, the lower limit of the kneading amount of the polyvinyl alcohol component is not particularly limited, but is usually 0.1 parts by mass or more, preferably 0.5 parts by mass or more with respect to 100 parts by mass of the solid waste.

  In this case, the dust scattering inhibitor aqueous solution is kneaded with the incineration fly ash. In the present invention, the dust scattering inhibitor aqueous solution is kneaded with the heavy metal fixing agent and the cement as described above even if kneaded alone. Also good. Moreover, it is also possible to add water as needed.

  After the kneading, for example, as shown in FIG. 1, the processing product p discharged from the kneading and molding machine 3 is conveyed by the conveyor 5 and temporarily stored in the processing bunker 6, and is transferred from the processing bunker 6 to a truck or the like. They are loaded and transported to the final disposal site. Also, at the final disposal site, it is unloaded from the truck and landfilled. At this time, the processing product p may generate dust due to impact in each process or operation of transportation, storage, transportation, unloading, and landfilling, but according to the method of the present invention and the aqueous solution for preventing dust scattering, It is possible to reduce dust generation as much as possible.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Example 1]
Using an apparatus as shown in FIG. 1, a kneading molding machine 3 of a device for adding and kneading a heavy metal fixing agent to incineration fly ash discharged from a waste incinerator and separated from exhaust gas is added to polyvinyl alcohol A dust scattering inhibitor aqueous solution containing 12% by mass of Poval Co., Ltd. JL-05E) and 0.4% by mass of potassium alginate (Snow Potassium M manufactured by Fuji Chemical Industry Co., Ltd.), respectively. Using a diaphragm pump from the tank 4, the polyvinyl alcohol component was added to 1.5 parts by mass with respect to 100 parts by mass of the incinerated fly ash and kneaded into the incinerated fly ash. In addition, 3 mass parts of heavy metal fixing agents (Fuji Sash Co., Ltd. L-301) were simultaneously added to the kneading molding machine 3 with respect to 100 mass parts of incineration fly ash. The kneaded molded product of incinerated fly ash was stored in a treated bunker for 1 day, and the dust scattering characteristics (scattering prevention characteristics of the dust scattering inhibitor) of the obtained kneaded molded article were evaluated by the following methods.

The dust scattering state was observed when the kneaded molded product was loaded onto the truck bed from the dust scattering treated bunker (falling about 2 m).

  As a result of the dust scattering evaluation, almost no dust soaring from the truck bed was observed, and a very slight soaring quickly settled and did not float.

500 g of the kneaded product (processed product) after storage in the processed dust bunker (A) and (B) (A) as it is (B) in a dryer (temperature 60 ° C., 1 hour) It dried and grind | pulverized for 60 minutes with the ball mill (ball | bowl non-use), and sieved using the sieve of 150 micrometers of mesh openings, and evaluated the ratio of 150-micrometer under-sieving goods (particle size less than 150 micrometers). The results are shown in Table 1.

[Comparative Example 1]
Except for not adding the dust scattering inhibitor aqueous solution, incineration fly ash was kneaded and molded in the same manner as in Example 1, and the dust scattering characteristics of the obtained kneaded molded product were evaluated by the above method.

  As a result of the dust scattering evaluation, a considerable amount of dust soared from the truck bed and floated, and did not settle.

  From the result of the evaluation of the dust scattering characteristics, it can be seen that the example in which the dust scattering inhibitor aqueous solution is added suppresses dust scattering better than the comparative example in which the dust scattering inhibitor aqueous solution is not added. Further, in the examples, the amount of fine dust generated by the pulverization operation by the ball mill is reduced compared to the comparative example in both the undried state and the dried state, and the method of the present invention and dust scattering prevention It can be seen that the aqueous solution of the agent is effective in preventing dust scattering of solid waste such as incineration fly ash discharged from the garbage incinerator.

It is the schematic explaining the process of processing incineration fly ash of the garbage incinerator to which the dust scattering prevention method of the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fly ash silo 2 Fixed quantity supply apparatus 3 Kneading molding machine 4 Dust scattering inhibitor aqueous solution tank 5 Conveyor 6 Processed bunker a Incineration fly ash b Dust scattering inhibitor aqueous solution p Processing product s Sample t Tray

Claims (9)

  A dust scattering prevention method comprising kneading an aqueous dust scattering inhibitor solution containing polyvinyl alcohol to solid waste discharged from a garbage incinerator.   The method for preventing dust scattering according to claim 1, wherein the polyvinyl alcohol content in the aqueous solution is 30% by mass or less.   The method for preventing dust scattering according to claim 1 or 2, wherein a polyvinyl alcohol component is kneaded at 3 parts by mass or less with respect to 100 parts by mass of the solid waste.   The dust scattering prevention method according to any one of claims 1 to 3, wherein the dust scattering inhibitor aqueous solution further contains a water retention agent.   5. The dust scattering prevention method according to claim 4, wherein the content of the water retention agent in the aqueous solution is 2% by mass or less.   The dust scattering prevention method according to any one of claims 1 to 5, wherein the solid waste is incineration fly ash.   An aqueous dust scattering inhibitor solution for solid waste discharged from a garbage incinerator, characterized by containing polyvinyl alcohol.   Furthermore, a water retention agent is contained, The dust scattering inhibitor aqueous solution of Claim 7 characterized by the above-mentioned. 9. The dust scattering inhibitor aqueous solution according to claim 7 or 8, wherein the solid waste is incinerated fly ash.

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